Differential plunger valve



Dec. 8, 1925. I 1,564,252

(3. w. LARNER Y DIFFERENTIAL PLUNGER VALVE Filed Nov. 4, 1921 77 Al 5 I]! 4 IN VEN TOR %w v A TTORNEYJ Patented Dec. 8, 1925.

UNITED STATES PATENT OFFICE.

CHESTER W. LARNER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR, BY DIRECT IAND MESNE ASSIGNMENTS, TO THE WILLIAM CRAMP & SONS SHIP & ENGINE BUILDING COMPANY, A CORPORATION OF PENNSYLVANIA.

DIFFERENTIAL PLUNGER VALV'E.

Application filed November 4, 1921, Serial No. 512,762.

To all whom it may concern:

Be it known that I, CHESTE W. LARNER,

acitizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania} have invented certain new and useful Improvements in Differential Plunger Valves, of which the following is a specification.

This invention relates to flow control systems and particularly to a valve control means for the flow through water mains.

The chief object of the invention is toprovide simpleand efficient means for governing the movement of a main control valve so that its degree and rate of opening or closing are at all times under complete control, Further objects of the invention particu- 'larly in the provision of simple and responsive restoring connections between the control means and valve plunger will appear from the following description taken in connection with the accompanying drawings, in which,

Fig. 1 shows sectional plan of the plunger valve with the control mechanism in position. and

Fig. 2 shows sectional elevation through the control valve on the line 2+2 of Fig.1.

The valve consists of a body 1 with an internal cylinder 2 supported and spaced from the body by radial ribs 3 providing a fluid way 4 in which flow. takes place in one direction only, namely, from left "to right in the drawing.

A plunger 5 co-operates with cylinder 2 to form an internal cylindrical chamber 6 and an annular chamber 7. The plunger 5 closes against a seat at the outlet end of the body Plunger 5 is opened by exhausting pressure from chamber 6 and admitting pressure to chamber 7; it is closed by reversing this operation. Pressure is exhausted from chamber. 6 by means of port 8 and from chamber 7 by means of port 9, both of these ports being controlled by mechanism outside the valve as described later. When plunger 5 is wide open or fully closed ports 8 and 9 are closed.

When pressure is exhausted from chamber 6 it must be. simultaneously supplied to chamber 7. This is particularly essential when plunger 5 is being unseated with the pipe line beyond the plunger empty. After established in the pipe line beyond the valve the pressure to chamber7 maybe adequately'supplied by leakage from fluid way 4 through the clearance between plunger 5 and cylinder 2, but in order to unseat the plunger additional provision must be made for supplyingpressure to chamber 7 or else the clearance space around the plunger must be made excessive. The latter is ob jectionable when it becomes necessary to exhaust chamber 7 to close the plunger and therefore it is advantageous to provide special means of supplying pressure to chamher 7 at the beginning of the opening stroke and cutting oft the supply as soon as the plunger is unseated. This may be accom plished by a by-pass port such as 10 which is open between fluid way 4 and chamber 7 when the plunger is closed and which cuts oil immediately after the plunger is unseated. An alternative method consists of providing longitudinal grooves 10 in the outside surface of the plunger, the length of these grooves being such that they act as a by-pass when the plunger .is unseated. The same thing may be accomplished by slightly reducing the diameter of the plunger all the way around the circum ference, but if this is done ribs 3 must be extended to act as a guide forrthe plunger as it approaches the closed position. The advantage of reducing the plunger diameter or grooving the surface as shown at 10s is that the passages admitting fluid to chamber 7 are small and act as a strainer, whereas port 10 must be relatively large and would permit the entrance of trash from the fluid way which would eventually have topass through the control valve and might obstruct it.

When pressureis exhausted from chamber 7 to close the plunger, pressure must be simultaneously su plied to chamber 6. This may be done in a variety of ways producing difi'erent effects and which may be determined to suit the individual conditions involved. Whichever of the methods described herein is adopted, however, the area of the port or ports supplyingipressure from the fluid way 4 to chamber 6 must be considerably less than the area of port 8 which is used to exhaust pressure from chamber 6, otherwise it would be impossible to reduce the pressure in chamber 6 sufliciently to open plunger 5.

' The pressure, may be supplied from the fluid way to chamber 6 by a port 11 in the rear end of cvlinder 2. This is a practicable method when the maximum velocity of flow through the valve is relatively low, but it flow and the relative velocities.

7 example, as at 11 slightly upstream from the seat between plunger 5 and body 1. At all positions of the plunger these ports are in a region of relatively high velocity and are free from the impact of the flowing water and therefore the pressure communicated to chamber 6 through ports 11 will at all times be lower than if communicated through port 11. The advantage of using a number of small ports 11 instead of one larger port of equivalent area consists in the strainer efl'ect thus secured and which has been already referred to.

Another location of the inlet port is 11". This is one port or an equivalent number of smaller ports located on the side of port 8 so as to avoid the impact of the flowing water. Such a port or ports will supply pressure to chamber 6 lower than that supplied by port 11 on account of eliminating the impact, but higher than that which would be supplied by 11 because the pressure in the fluid way at 11 is higher than that at'll 'when plunger 5 is open.

Another alternative is 11, the port being placed in the downstream side of port 8, thus securing a certain sucking or ejector effect which tends to reduce the pressure communicated to chamber 6.

It is obvious that many different positions may be devised for this inlet port and different results accomplished thereby, according to the judgment of the designer.

Fig. 2 shows a section through the external control valve which is utilized to exhaust pressure from chambers 6 and.7. This control valve consists of a cylindrical body 12 provided with connections to exhaust ports Sand 9 and a connection 13 for discharging .the fluid exhausted from chambers 6 and 7 to the atmosphere. Control valve body 12 has two circumferential ports 14 and 15, the discharge through which is controlled by a sleeve valve 16 operated from the exterior by a stem 17 Valve 16 is so designed that it uncovers only one port at a time; that is to say, if pressure is being exhausted'from'6 it is being retained in 7 and vice versa. It is obvious that in operating plunger 5 by exhausting either chamber 6 or chamber 7, if these chambers are freely exhausted, there is no restraint upon the rate at which plunger 5 moves except the rate at which fluid can be supplied to the other of these chambers 6 and 7 through the fixed passages leading to the fluid way, which are provided for this purpose. This method of control is uncertain and unreliable and, furthermore, will not suffice to hold the plunger stationary at positions intermediate between open and closed. It is therefore desirable to provide an operating gear for valve 16 connected in some manner to plunger 5 in order to secure a co-ordinated relation between the motion of the control valve 16 and plunger 5. This is secured in the following manner: A rod 18 is connected to plunger 5 by a hearing 19 in which rod 18 is free to turn so that plunger 5 may rotate without rotating rod 18. Rod 18 has a rack 20 at the rear end which engages a pinion on shaft 21 in such manner that when plunger 5 opens, shaft 21 rotates counter-clockwise as viewed in Fig. 2. A hearing 22 supported from cylinder 2 serves to guide rack 20 and shaft 21 in a manner familiar in the art.

A hand mechanism for operating valve 16 is mounted on the exterior end of shaft 21. This mechanism is not shown in Fig. 1 but is shown in Fig. 2. It consists of a lever 32 mounted on shaft 21 but free to turn thereon and a cover plate 23 in front of lever 32 and also free to turn on shaft 21. A worm wheel 24 is mounted on shaft 21 in a position between 32 and 23 and is keyed to shaft 21. Cover plate 23 and lever 32 are properly spaced to accommodate worm wheel 24 and are fastened together by bolts 25 and 26 with worm shaft 27 between them and the bearings for it clamped between these two parts. A hand wheel. 28 is mounted on shaft 27.

To close plunger 5 hand wheel 28 is turned in the proper direction to rotate lever 32 counter-clockwise, lever 32 being connected to valve stem 17 by connecting rod 29. Valve 16 is moved to the left thus uncovering port 15 as shown in Fig. 2 and exhausting pressure from chamber 7. As soon as plunger 5' starts to move, however, shaft 21 will rotate clockwise tending to restore valve 16 to its original position, thus closing port 15. This will check the motion of plunger 5 which can be then continued only by further turning of lever 32 counterclockwise. It is thus seen that the motion ofplunger 5 is co-ordinated to the motion of hand wheel 28 and that thestroke of plunger 5 may be made as slowly or as rapidly as desired or that plunger o mav be held stationary at intermediate positions. Any tendency of plunger 5 to over-travel is immediately corrected by the restoring action of the mechanism connected to the plunger. If the closing of the port which may be open is not suflicient to stop the over-travel of plunger 5 the continued motion of valve 16 will then open the other port and exhaust pressure from the other of chambers 6 or 7, thus actually reversing the motion of plunger 5.

The opening operation of plunger 5 is the opposite of the closing operation just described, lever 32 being rotated clockwise by means of the hand mechanism and restored in a counter-clockwise direction by the rotation of shaft 21. If the valve is discharging into a region of relatively low pressure, as, for example, in the case of a blow-01f valve in a dam outlet, it is not necessary to exhaust chamber 7 to close plunger 5 because the pressure on the outside of the plunger nose is low and the application of fluid way pressure in chamber 6 is more than sufficient to close the plunger. In such cases ports 9 and 15 may, therefore, be omitted and valve 16 used to exhaust chamber 6 only. Valve 16. is then made only long enough to cover port 14.. Otherwise the construction and operation are unchanged.

A feature of novelty of this invention consists in the combination of a control valve exhausting pressure from the two operating chambers of the main valve without supplying pressure to either of these chambers, the latter being supplied by-fixed openings through the internal structure of the main valve. The sleeve valve is in practically perfect balance and requires little power to operate it and its connections to the main valve plunger may be light.

Another novel feature ,is the restoring mechanism shown consisting of the rotating lever 32 on the shaft 21 which is connected to plunger 5, lever 32 being rotated with respect to the shaft 21 by means of a worm and Worm wheel, and this restoring mechanism is very compact and convenient. An important feature is the improvement or principle of operating a differential plunger valve by means of two exhaust ,valves, the latter being combined in one structure as shown in the present instance or separated into two. separate exhaust valves suitably connected-together.

A very important result is accomplished by the novel arrangement used for connecting shaft 21 to plunger 5. In order to secure precise control of the movement of plunger 5 it is essential that the movement of the plunger should produce a relatively large counteracting movement of the control valve 16. If the restoring movement of the control valve is too small relative to the movement of the plunger, the plunger will tend to drift and cannot be controlled with precision. It may, under some circumstances be advantageous to have the linear travel of the control valve greater than the linear travel of the plunger.

It is obvious that any ratio of travel may be secured by varying the size of the pinion on shaft 21 which engages rack 20.

In this way shaft 21 .can be made to rotate any number of turns during the stroke of the plunger.

I claim 1. The combination with a conduit, of a plunger valve closing in the direction of flow and having two internal operating chambers to each of which pressure is supplied through openings provided in theinternal structure of the valve wholly within said conduit, and a single exhaust valve 7 nular operating chambers to each of which pressure is supplied through openings provided in the internal structure of the valve wholly within said conduit, and a single exhaust valve connection for each chamber, substantially as described. v

4. The combination of a plunger valve having cylindrical and annular operating chambers to each of which pressure is supplied through openings provided in the 1nternal structure of the valve, and a control valve devoid of pressure connections and 7 having exhaust connections for said chambers, substantially as described.

5. The combination with a conduit, of a plunger valve having internal cylindrical and annular'operating chambers to each of which pressure is supplied through openings provided in the internal structure of the valve wholly within said conduit, and a single exhaust valve connection for each chamber, substantially as described.

6. The combination of a plunger valve having internal cylindrical and annular operating chambers to each of which pres sure is supplied through 0 enings provided in the internal structure 0 the valve, and a control valve devoid of pressure connections and having exhaust connections for said chambers, substantially as described.

7. The combination with a conduit, of a plunger valve having internal cylindrical and annular operating chambers to each of which pressure is supplied through open ings provided in the internal structure of the .valve wholly within said conduit, an exhaust valve casing, exhaust connections from each of said chambers to theinterior of said exhaust valve casing, and a balanced reciprocating control valve adapted to uncover one or the other of said exhaust connections, but not both, substantially as described.

8. The combination of a plunger valve having internal cylindrical and annular on the shaft, a worm and worm-wheel con? necting the lever, and shaft, and a controlling valve operated by. the lever, substantially as described.

10. In a plunger valve the combination of a casing, an internal structure between which and the casing there is a fluid way and which rovides cylindrical and annular operating c ambers to each of which pressure is supplied from the fluid way by openings provided in the internal structure and stopping short of the casing, exhaust connections through the casing and across the fluid way to the chambers, and exhaust valves for the exhaust connections.

11. The combination with a conduit, of a plunger valve having a fluid way and internal cylindrical and annular operating chambers each supplied with pressure from the fluid way by passages provided in the internal structure of the valve wholly with in said conduit, exhaust valves for discharging pressure from said chambers and a reciprocating connection between the exhaust valves and the plunger whereby the opening of the exhaust valves is checked or counteracted by the resulting movement of the plunger.

12. The combination with a casing and a hollow valve herein formed of a stationary part and a movable plunger means for operating said valve, a control valve for said operating means, and restoring mechanism between the plunger and the control valve comprising a rotatable shaft extending from Within the hollow valve to the outside of the conduit, means within the hollow valve for rotating said shaft and an adjustable connection between said shaft and said control Valve.

13. In a flow control system a conduit, a hollow valve within said conduit comprising a fixed member having a tapering portion with an opening to conduit pressure in the end thereof and a relatively movable member with a tapering closed end, said members being formed to provide a central chamber and a surrounding annular chamber, and means for connecting said chambers to 160w pressure to'control said movable mem- 14. The combination with a casing and a hollow valve therein formed of a stationary part and a movable plunger seating against said casing, and means for operating said valve comprising a fluid pressure chamber within said plunger and an opening connecting the interior of said plunger t0 the fluid way, said opening being located slightly upstream from the seat between the plunger and the body of the casing.

CHESTER W. LARNER. 

